Appliance for and method of making concrete structures



J. E. MILLER ,040,666 APPLIANCE FOR AND METHQD OF MAKING CONCRETE 'STRUCTURES May 12, 1936 Filed Nov. 5, 1934 INVENTOR.

AITTORNEK,

Patented May 12, 1936 APPLIANCE FOR AND-METHOD OF MAKING- CONCRETE STRUCTURES Joseph Edwin Miller, Fort Wayne, Ind. Application November 5,1934, Serial No. 751,479

8 Claims.

This invention relates to improvements in an appliance for and method of making concrete structures. The object of the invention is to provide means and a method for the manufacture of various bodies of concrete whereby when completed said bodies will be of greater density and strength than when made in the ordinary manner, and the exposed surfaces thereof will be of increased smoothnes and substantially free from pits caused by air or water globules that ordinarily become entrapped in the concrete mixture and are retained during the subsequent setting process thereof, and also free from blemishes that frequently occur due to lack of unifomity of moisture in-the newly poured concrete mixture. Other objects and advantages of the invention will appear in the following description.

An illustrative embodiment of the appliance in a preferred form for use in the manufacture of concrete bodies by my new method is illustrated in the accompanying drawing, in which:

Fig. 1 is an elevation of a structure in which an agitating appliance is embodied, and includes also a concrete-containing form used in conjunction therewith, said form and its concrete content being shown in section; and

Fig. 2 is a fragmentary plan view of the form projected from Fig. 1 and in which the agitator rod is shown in cross-section.

appliance used in carrying out the method herein disclosed for making concrete bodies consists of an agitator rod I, preferably pointed at one end, polygonal in cross-section and twisted so that its faces have spiral formation; and an activator for rotating the agitator rod upon its axis, preferably an electric motor 2 to which the agitator rod is connected at one end as by a chuck 3. The motor has a handle 4 and a conveniently located switch 5 as is usually provided for the motor of an electrically-driven drill. Current is supplied to the motor through suitable conductors 6 that extend through a flexible covering 1 therefor attached to the handle, and which connect the 4 motor with aproper source of energy (not shown).

The equipment for carrying out my method includes the form into which the freshly-mixed concrete is initially poured preparatory to treatment'with the agitating appliance. The form is of any suitable structure such, for example, as

one having walls 8-9 superimposed upon a base ID to provide a concrete-containing chamber H with an open top, and arranged so that the concrete placed in the chamber, when set, will result in a body of the desired shape.

The illustrative embodiment of the agitating The method An especial feature of the invention is the man ner of treating the concrete poured into the form, while in the state of plasticity before setting of the concrete commences. This method consists in agitating the plastic concrete in the form more or less locally throughout its various portions, in such manner as to break up and liberate pocketed air and surplus water from the mass 'of material while in the state of plasticity, and consists also in troweling the concrete during agitation thereof against the inner faces of the walls of the form to insure smoothness of the molded surfaces of the concrete body when finally completed. The agitation of the plastic concrete in the manner herein disclosed is distinct from the ordinary practices of vibrating the form by various means; spading or tamping the poured concrete while' plastic; or by shaking the plastic mass by inserting therein various vibratory im-. plements. In all of such practices there is tendency of the course aggregatein the concrete to seggregate and become packed unevenly without liberating the pocketed air and surplus water. In the present method, however, the plastic mass is stirred in such manner that the fine and coarse aggregate are kept uniformly mixed and the pocketed air and surplus water is liberated so that the concrete body when finally'completed is both dense and uniform throughout its portions.

The operation In making the concrete body, freshly-mixed concrete is poured into the mold as in the usual practice, and during the pouring operation, or, after the concrete is poured and still in the state of plasticity in the form, the agitator rod I is rotated upon its axis by turning on the motor, and while rotating, the rod is thrust endwise into the plastic mass. The rotating rod has a tendency to travel laterally or crawl about in the wet concrete. This movement is manually guided by manipulation of the handle of the motor, which requires but little physicalelfort. In this man-' ner the agitator is moved at will so as to traverse substantially all portions of the concrete contained in the form. 7

An advantageous feature of the agitating appliance is that its rod I is of small diameter which preferably is not materially greater than is necessary for it to withstand'the torsional strain imposed upon it by the action of the motor, and also. the resistance of the wet concrete to its lateral travel therethrough, Being thin, the rod when inserted into the concrete causes only negligible displacement thereof and its lateral travel through the mass of concrete is rapid and effective. Thus the poured concrete in the form is subjected throughout all portions of its mass to agitation necessary to preserve uniformity in the mixtureof its aggregate and liberation of entrapped air and surplus water.

In making reinforced concrete bodies in which are embedded reinforces such as metal bars |2-l3 which ordinarily are positioned in the concrete mass at points spaced approximately one inch inwardly from the inner faces of the form, the agitating rod is guided in its lateral travel between the reinforces and the adjacent retaining wall of the form, substantially in a course indicated by the dotted line l4. By traveling the rotating rod along a path closely adjacent to the form, the concrete is thereby troweled against the faces of the form, resulting in corresponding smoothness of the molded faces of the finished product.

By using a rod with left-handed spiral formation and applying it with right-hand rotation, or vice versa, the concrete surrounding the rod tends to compress downwardly and causes compactness of its aggregate. The lateral travel of the rod, however, leaves a wake in its path up through which escape of entrapped air and surplus water takes place. Thus, the concrete in the form is left in a dense mass to set after the rod is removed.

I claim:

1. An agitator for treating freshly-mixed concrete poured into a form consisting of a thin rod having lateral faces, and an activator connected with one end of the rod for axial rotation thereof, said agitator being manually movable.

2. An agitator for treating freshly-mixed concrete poured into a form consisting of a thin rod having faces disposed in spiral formation, and an activator connected to one end of the rod for axial rotation thereof, said agitator being manually movable.

3. The method of treating freshly-mixed concrete while plastic in a form, which method consists in agitating the various portions of the concrete successively by inserting and revolving therein a thin rod, and manually moving said rod laterally while rotating to thereby breakup and liberate pocketed air and surplus water from the concrete mass.

4. The method of treating freshly-mixed concrete in a form which method consists of the insertion of a thin rod into the concrete, revolving said rod and moving it laterally throughout the various portions of the concrete mass to break up and liberate pocketed air and surplus water therefrom. a

5. The method of treating freshly-mixed concrete in a form, which method consists of inserting into the concrete while plastic and contained in said form a spirally formed rod, and simul-.

taneously rotating said rod upon its axis and manually moving said rod throughout the various portions of the concrete mass,

6. The method of treating freshly-mixed concrete in a form, which method consists of inserting into the concrete while plastic a rod angular in cross-section, revolving said rod and moving said rod while revolving so as to traverse the various portions of the concrete mass.

7. The method of treating freshly-mixed concrete in a form, which method consists in troweling the contained concrete against the inner faces of the form by inserting into the concrete an agitator rod, revolving said rod, and traveling said rod through the concrete mass laterally in a path closely adjacent said faces.

8. An agitator for treating freshly-mixed con crete poured into a form, said agitator consisting of a thin rod and an activator connected with one end of said rod adapted to axially rotate said rod, said activator having a handle for manually maneuvering the agitator laterally while said rod is rotated in the concrete.

JOSEPH EDWIN MILLER. 

